Commit c7b5a4e6 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

PCI / PM: Fix native PME handling during system suspend/resume 



Commit 76cde7e4 (PCI / PM: Make PCIe PME interrupts wake up from
suspend-to-idle) went too far with preventing pcie_pme_work_fn() from
clearing the root port's PME Status and re-enabling the PME interrupt
which should be done for PMEs to work correctly after system resume.

The failing scenario is as follows:

 1. pcie_pme_suspend() finds that the PME IRQ should be designated
    for system wakeup, so it calls enable_irq_wake() and then sets
    data->suspend_level to PME_SUSPEND_WAKEUP.

 2. PME interrupt happens at this point.

 3. pcie_pme_irq() runs, disables the PME interrupt and queues up
    the execution of pcie_pme_work_fn().

 4. pcie_pme_work_fn() runs before pcie_pme_resume() and breaks out
    of the loop right away, because data->suspend_level is not
    PME_SUSPEND_NONE, and it doesn't re-enable the PME interrupt
    for the same reason.

 5. pcie_pme_resume() runs and simply calls disable_irq_wake()
    without re-enabling the PME interrupt (because data->suspend_level
    is not PME_SUSPEND_NONE), so the PME interrupt remains disabled
    and the PME Status remains set.

To fix this notice that there is no reason why pcie_pme_work_fn()
should behave in a special way during system resume if the PME
interrupt is not disabled by pcie_pme_suspend() and partially revert
commit 76cde7e4 and restore the previous (and correct) behavior
of pcie_pme_work_fn().

Fixes: 76cde7e4 (PCI / PM: Make PCIe PME interrupts wake up from suspend-to-idle)
Reported-and-tested-by: default avatarNaresh Solanki <naresh.solanki@intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent 0ce3fcaf

drivers/pci/pcie/pme.c

+13 −22
Original line number Diff line number Diff line
@@ -40,17 +40,11 @@ static int __init pcie_pme_setup(char *str) 
}

__setup("pcie_pme=", pcie_pme_setup);



enum pme_suspend_level {

	PME_SUSPEND_NONE = 0,

	PME_SUSPEND_WAKEUP,

	PME_SUSPEND_NOIRQ,

};



struct pcie_pme_service_data {

	spinlock_t lock;

	struct pcie_device *srv;

	struct work_struct work;

	enum pme_suspend_level suspend_level;

	bool noirq; /* If set, keep the PME interrupt disabled. */

};



/**
@@ -228,7 +222,7 @@ static void pcie_pme_work_fn(struct work_struct *work) 
	spin_lock_irq(&data->lock);



	for (;;) {

		if (data->suspend_level != PME_SUSPEND_NONE)

		if (data->noirq)

			break;



		pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);
@@ -255,7 +249,7 @@ static void pcie_pme_work_fn(struct work_struct *work) 
		spin_lock_irq(&data->lock);

	}



	if (data->suspend_level == PME_SUSPEND_NONE)

	if (!data->noirq)

		pcie_pme_interrupt_enable(port, true);



	spin_unlock_irq(&data->lock);
@@ -378,7 +372,7 @@ static int pcie_pme_suspend(struct pcie_device *srv) 
{

	struct pcie_pme_service_data *data = get_service_data(srv);

	struct pci_dev *port = srv->port;

	bool wakeup, wake_irq_enabled = false;

	bool wakeup;

	int ret;



	if (device_may_wakeup(&port->dev)) {
@@ -388,19 +382,16 @@ static int pcie_pme_suspend(struct pcie_device *srv) 
		wakeup = pcie_pme_check_wakeup(port->subordinate);

		up_read(&pci_bus_sem);

	}

	spin_lock_irq(&data->lock);

	if (wakeup) {

		ret = enable_irq_wake(srv->irq);

		if (ret == 0) {

			data->suspend_level = PME_SUSPEND_WAKEUP;

			wake_irq_enabled = true;

		}

		if (!ret)

			return 0;

	}

	if (!wake_irq_enabled) {



	spin_lock_irq(&data->lock);

	pcie_pme_interrupt_enable(port, false);

	pcie_clear_root_pme_status(port);

		data->suspend_level = PME_SUSPEND_NOIRQ;

	}

	data->noirq = true;

	spin_unlock_irq(&data->lock);



	synchronize_irq(srv->irq);
@@ -417,15 +408,15 @@ static int pcie_pme_resume(struct pcie_device *srv) 
	struct pcie_pme_service_data *data = get_service_data(srv);



	spin_lock_irq(&data->lock);

	if (data->suspend_level == PME_SUSPEND_NOIRQ) {

	if (data->noirq) {

		struct pci_dev *port = srv->port;



		pcie_clear_root_pme_status(port);

		pcie_pme_interrupt_enable(port, true);

		data->noirq = false;

	} else {

		disable_irq_wake(srv->irq);

	}

	data->suspend_level = PME_SUSPEND_NONE;

	spin_unlock_irq(&data->lock);



	return 0;

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